I tryed to launch seamonkey-2.56a1.en-US.win64 (2018-01-10-03-01-07-comm-central-trunk/) from temp dir. Alpha succefully get settings from profile, but lost bookmarks. When i returned to 2.49.1 bookmarks not appears. All attempts to restore bookmarks by bookmarks-manager was failed: "Unable to bla-bla.." When I replace current places.sqlite from old backup, all bookmarks returned. Is it bug?

I'm moving this to the Builds forum which is a better place for pre-release version discussion.

Give a man a fish, and he eats for a day. Teach a man to fish, and he eats for a lifetime.I like poetry, long walks on the beach and poking dead things with a stick.Please do not PM me for personal support. Keep posts here in the Forums instead and we all learn.

The internal format of the bookmarks database places.sqlite changed between 2.49 and 2.56. You should not have lost the bookmarks during the upgrade but 2.56 is in a bad shape right now anyway which might have cuased it. We will retest it when it is in working order again (will probably take some time).

Going back was never supported so it might work or not. Usually indexed DB format also changes every second or third release and you have problems afterwards. So if you want to go back always use a backup unless you really know what changed and could fix it manually.